In order to provide a three-dimensional molded object production method in which warping deformation is reduced, one embodiment of the present invention provides a three-dimensional molded object production method in which powder layer formation and solidified layer formation through light beam irradiation are repeatedly performed, wherein a plate layered body is used as a foundation for the three-dimensional molded object, said plate layered body having a molding plate and a dummy solidified layer, and the dummy solidified layer is provided on one main surface of the molding plate, while the three-dimensional molded object is produced on another main surface of the molding plate.